Synthesis and pharmacological evaluation of a series of dibenzo[a,d]cycloalkenimines as N-methyl-D-aspartate antagonists.

A series of 73 dibenzo[a,d]cycloalkenimines were synthesized and evaluated for their ability to displace (+)-10,11-dihydro-5-methyl-5H-dibenzo[a,d]cyclohepten-5,10-imine ([3H]-(+)-10) from its specific binding site on rat cortical membranes. A number of the more active compounds (Ki ranging from 0.006 to 0.21 microM) were evaluated for N-methyl-D-aspartate (NMDA) antagonist activity in the rat cortical slice (Kb ranging from 0.08 to 0.9 microM) and anticonvulsant activity in the mouse against NMDA induced convulsions. The ED50 values ranged from 0.22 to 7.76 mg/kg and correlated reasonably well with the Kb determination. In the dibenzo[a,d]cyclohepten-5,10-imine series, the (+)-5S,10R enantiomer displayed consistently higher levels of biological activity. While substitution at the 3-position of (+)-10 with electronegative atoms generally increased in vitro activity, a loss of potency relative to (+)-10 (MK-801) was observed in vivo for all of the compounds tested.     

Effect produced by acute and chronic administration of the selective 5-HT3 receptor antagonist BRL 46470 on the number of spontaneously active midbrain dopamine cells in the rat

This study examined the effect of acute and chronic administration of the selective 5-HT₃ receptor antagonist BRL 46470A, an analog of granisetron, on the number of spontaneously active dopamine (DA) cells in the substantia nigra pars compacta (A9 or SNC) and the ventral tegmental area (A10 or VTA) in the rat. In the A10 area, the acute administration of BRL 46470A decreased the number of spontaneously active DA cells at a dose of 0.1 mg/kg (0.28 μmol/kg) ip, yet increased the number of spontaneously active DA cells at a dose of 0.3 mg/kg (0.84 μmol/kg). The chronic administration (21 days) of BRL 46470A appeared to produce a multiphasic dose-response curve. Thus, the chronic treatment with BRL 46470A increased the number of spontaneously active A10 DA cells at 0.03 (0.084 μmol) and 0.3 mg/kg, but decreased the number of spontaneously active A10 DA cells at a dose of 0.1 mg/kg. In contrast, BRL 46470A did not decrease the number of spontaneously active A9 DA cells after either acute or chronic administration (0.01-0.3 mg/kg). However, BRL 46470A did increase the number of spontaneously active A9 DA cells at acute and chronic doses similar to those that were effective in A10. The iv administration of (+)-apomorphine (APO) not only failed to reverse the decrease produced by chronic administration of BRL 46470A at 0.1 mg/kg, but further decreased the number of spontaneously active A10 DA cells. Similar to the results obtained with granisetron, the pretreatment of naive rats with either 0.01 or 0.1 mg/kg iv of BRL 46470A significantly potentiated (2-fold) the suppressant action of APO on the basal firing rate of A10, but not A9 DA cells. Overall, our results indicate that similar to granisetron, chronic BRL 46470A at 0.1 mg/kg selectively decreases the number of spontaneously active A10 DA cells, via a mechanism not related to depolarization inactivation. Presently, it is not clear what factors may contribute to the multiphasic dose-response curve of BRL 46470A. © 1994 Wiley-Liss, Inc.     

Synthesis and pharmacological investigation of beta-substituted pyrrolo derivatives

A series of pyrroles bearing an ethanol- or an iso-propanolamine side-chain in the beta-position was prepared and their adrenergic activity evaluated. The absence of any appreciable activity suggests that the pyrrole ring is not suitable for replacing the phenol nucleus in derivatives possessing an adrenergic activity. Noteworthy is the amphetamine-like activity observed in amino-ketone (XXIII).     

Safety and effect of transforming growth factor-β2 for treatment of venous stasis ulcers

Transforming growth factor-beta(2) promotes healing in a variety of animal models and exhibits clinical effects thought to be mediated by connective tissue formation. Two clinical trials were conducted to evaluate the safety and effect of transforming growth factor-beta(2) purified from bovine bone and delivered topically to venous stasis ulcers three times per week for up to 6 weeks by means of a lyophilized collagen vehicle. The first was an open-label trial comparing transforming growth factor-beta(2) purified from bovine bone (0.5 microg/cm(2)) with a placebo consisting of lyophilized collagen vehicle-without active drug. After no safety issues arose in that trial, a prospectively randomized, closed-label, observer-blinded, three-armed trial was conducted to compare bovine transforming growth factor-beta(2) (2.5 microg/cm(2)) with the collagen matrix placebo vehicle and with a standard dressing. Standardized elastic compression was applied to all test extremities. The rate of reduction of ulcer area as measured by planimetry was the primary measure of effect. No serious safety-related events occurred in either trial. Clinical evaluation suggested that improvement in the quality and quantity of granulation tissue appeared to precede epithelialization of ulcers treated with bovine transforming growth factor-beta(2). In both studies, treatment with bovine transforming growth factor-beta(2) appeared to have a positive effect on the rate of ulcer closure, whereas ulcers in the control groups continued to exhibit impaired healing. In the open-label study, the mean rate of closure of ulcers treated with bovine transforming growth factor-beta(2) was significantly greater than that of ulcers treated with placebo. There was likewise enhanced reduction in ulcer area in the ulcers treated with bovine transforming growth factor-beta(2) in the second trial. However, because of a higher variability in patient response and a greater placebo effect, the difference was not significant. The placebo was not worse than the standard care arm, thereby showing that the vehicle is not injurious to healing. The combined results of the two trials suggest that, at doses of 0.5 to 2.5 microg/cm(2), bovine transforming growth factor-beta(2) is safe as a topically applied agent in a collagen matrix vehicle and can have a positive effect on closure of venous stasis ulcers. Large multicenter trials appear to be indicated to evaluate fully the potential utility of transforming growth factor-beta(2) in accelerating closure of chronic dermal ulcers.     

Development of a monoclonal antibody specific for beta/A4 amyloid in Alzheimer's disease brain for application to in vivo imaging of amyloid angiopathy.

We evaluated the efficacy of murine monoclonal antibodies (Mabs) targeted to beta/A4 amyloid for development of procedures for the in vivo identification of amyloid angiopathy (AA) in Alzheimer's disease (AD). Mabs to beta/A4 amyloid were prepared and screened for effectiveness in visualizing AA and senile plaques in postmortem AD brain sections. They were assessed again after enzymatic cleavage to produce Fab fragments and after labeling with 99mTc using a diamide dimercaptide ligand system. Modified and radiolabeled Fab fragments retained activity and specificity towards amyloid-laden blood vessels and senile plaques. A highly specific murine Mab, 10H3, was identified and characterized that fulfills criteria necessary for the development of a diagnostic imaging agent. Expansion and adaptation of these strategies may provide the methods and materials for the noninvasive analysis of AA in living patients, and permit assessment of the contribution of AA to the clinical and pathological features of AD.     

Preclinical hypogonadism in genetic hemochromatosis in the early stage of the disease: evidence of hypothalamic dysfunction.

We studied endocrine functions at baseline and after TRH and LHRH stimulation in a group of 7 young male patients with genetic hemochromatosis (HE) without liver damage (i.e. fibrosis and cirrhosis). In five patients endocrine re-evaluations after complete iron depletion was also performed. Mean basal testosterone (T), FSH, LH and PRL were significantly lower than in controls. Serum T increased normally after HCG stimulation. The normal or high increments of LH after LHRH stimulation suggest that secretion capacity of LH was intact and that hypothalamic dysfunction could be responsible for the preclinical gonadal deficiency found in our patients. The response of PRL to TRH indicates that secretion capacity of lactotrophs although present, was decreased and did not improve after phlebotomy therapy. After iron depletion the two patients with the lowest basal T levels showed the highest increments indicating that in the early stages of hypothalamic-pituitary damage gonadal dysfunction is still reversible in HE patients.